Falsework/Scaffolding Load Estimator Calculator

Formula Used

The estimator separates dead loads (concrete + formwork + added dead) from variable loads (live + equipment + workers + point loads). Then it applies factors for design checks.

How to Use This Calculator

1. Select your units and enter the supported area.
2. If using geometry, enter length, width, and leg spacing.
3. Enter slab thickness and density to estimate concrete load.
4. Add any extra dead load and expected live construction load.
5. Include equipment as a distributed load or as a point load.
6. Enter leg rating and base plate area from your system details.
7. Set safety and load factors to match your project criteria.
8. Press calculate, then review capacity and bearing results.

1) Why supported-area load matters

Fresh concrete and temporary construction actions can create short-duration peak demands that exceed finished-floor assumptions. This estimator starts with supported area so you can compare planning loads across bays, decks, and pour sequences, then scale totals consistently.

For staged placements, check the largest active footprint and any material stockpiles near edges. Localized stacking, hose reactions, and crew clustering can govern leg demand even when average area load appears acceptable.

2) Concrete dead load from thickness and density

Concrete dead load is calculated as density multiplied by thickness. Normal-weight concrete is often around 24 kN/m³ (roughly 150 pcf). A 200 mm slab therefore contributes about 4.8 kN/m² before adding reinforcement, screeds, or toppings.

3) Added dead and system weight

Formwork panels, joists, walers, and accessories add predictable dead load. Many projects also include embedded items or temporary edge protection. Enter these items as “Additional Dead Load” and “System Weight” so the base demand reflects your actual temporary works package.

4) Live construction and equipment loads

Construction live loads vary by activity. Placing operations, finishing, and material staging can raise demands quickly. For small tools, a distributed equipment load is practical. For pallets, pump-line reactions, or bundled materials, use the concentrated load input to stress the leg grid.

5) Factors: impact, distribution, and design multipliers

Impact factors capture dynamic effects from moving loads, vibration, and placement actions. Distribution factors allow for uneven load sharing, imperfect plumbness, and local stiffness differences. The dead and live multipliers convert service totals into a factored design total for checking support capacity.

6) Estimating leg count from spacing

When you select the geometry method, the calculator builds an approximate grid from length, width, and spacing. A 10 m × 5 m bay at 1.5 m spacing yields about 36 legs. Tighter spacing reduces load per leg but increases setup time and components.

7) Capacity check and required legs

Each leg is checked against a design allowable derived from its rating divided by a capacity safety factor. The utilization percentage highlights margin. If utilization exceeds 100%, increase leg count, reduce point loads, revise factors, or confirm a higher-rated standard and ledger configuration.

8) Bearing pressure and base support

Bearing pressure is computed as design load per leg divided by base contact area. The design allowable bearing is the site value divided by a bearing safety factor. If bearing fails, increase sole-board size, improve subgrade, redistribute legs, or use engineered foundations for temporary works.

Q1. What is the difference between service total and design total?

A. Service total summarizes unfactored loads for planning. Design total applies load multipliers, impact, and distribution to check leg capacity and bearing with a conservative margin.

Q2. When should I use a concentrated load instead of distributed equipment load?

A. Use concentrated load for pallets, stacked materials, pump-line reactions, or any item that bears on a small footprint. Use distributed equipment load for light tools and uniform staging.

Q3. How do I choose a reasonable impact factor?

A. Start near 1.05–1.15 for controlled placing and light vibration. Use higher values if loads move quickly, vibration is significant, or handling is rough. Match project temporary works criteria when available.

Q4. Why does bearing fail even when leg capacity passes?

A. A strong leg can still overload weak ground. Bearing depends on base area and soil allowable value. Increase base area with sole boards, improve ground preparation, or reduce design load per leg.

Q5. Is spacing the same as bay size?

A. No. Spacing is the distance between adjacent legs in the grid. Bay size is the overall supported length and width. Smaller spacing increases legs and lowers load per leg.

Q6. What inputs most affect required legs?

A. Supported area, slab thickness, live construction load, and point load drive totals. Leg rating and capacity safety factor control allowable per leg, while distribution and impact factors raise the design demand.

Q7. Can I rely on this output for final sign-off?

A. Use it for preliminary sizing and documentation. Final designs should confirm layout, bracing, connections, eccentricities, uplift, and local requirements through qualified engineering review.